Long-life corrosion-resistant Al / MAX composite coating as well as preparation method and application thereof

Abstract

The invention discloses a long-life corrosion-resistant Al / MAX composite coating as well as a preparation method and application thereof, and belongs to the technical field of protective coatings. The long-life corrosion-resistant Al / MAX composite coating comprises a bottom layer and a surface layer, wherein the bottom layer is composed of at least one bottom layer unit, and each bottom layer unit is composed of an Al layer and an MAX phase layer; in two adjacent bottom layer units, the Al layers and the MAX phase layers are alternately arranged; the surface layer is an Al surface layer; in each bottom layer unit, the thickness ratio of the Al layer to the MAX phase layer is 10: 1 to 30: 1. The long-life corrosion-resistant Al / MAX composite coating has better compactness and uniformity, shows excellent corrosion resistance, and can prolong the service life of parts in a marine environment.

Description

Technical Field

[0001] This invention relates to the field of protective coating technology, and more specifically, to a long-life corrosion-resistant Al / MAX composite coating, its preparation method, and its application. Background Art

[0002] Fasteners and structural components are among the most commonly used mechanical parts, and their reliability directly affects the lifespan and safety of the entire equipment. However, in high-salt and high-humidity marine environments, the risk of corrosion failure of key components such as fasteners and landing gear in high-end equipment like marine aviation and offshore wind power surges. Cadmium electroplating has been widely used as a primary corrosion-resistant protective measure. However, with a deeper understanding of the hazards of cadmium, its application is gradually being limited, necessitating the development of new long-life, corrosion-resistant protective coatings and green, pollution-free preparation technologies.

[0003] Al coatings possess excellent comprehensive protective capabilities, including good corrosion resistance, environmental friendliness, high-temperature resistance, and UV resistance. Firstly, the dense oxide film formed on the aluminum coating surface mechanically prevents corrosive media from directly contacting the substrate and causing corrosion. Secondly, the aluminum coating provides cathodic protection as a sacrificial anode, avoiding galvanic corrosion between metal parts. More importantly, Al coatings do not cause hydrogen embrittlement in the substrate, making them a preferred protective coating material for fasteners and structural components in high-end equipment. Studies show that the corrosion resistance of Al coatings is related to their structural density and thickness; the denser and thicker the coating, the longer its corrosion resistance life. However, during magnetron sputtering vacuum deposition of Al coatings, the continuous growth of columnar crystals easily forms microscopic gaps, reducing the coating's density. The longer the coating growth time, the more pronounced the gaps become, which is highly detrimental to corrosion protection.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a long-life, corrosion-resistant Al / MAX composite coating, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a long-life corrosion-resistant Al / MAX composite coating, the long-life corrosion-resistant Al / MAX composite coating comprising a base layer and a top layer; The bottom layer consists of at least one bottom layer unit, and each bottom layer unit consists of an Al layer and a MAX phase layer; in two adjacent bottom layer units, the Al layer and the MAX phase layer are alternately arranged. The surface layer is an Al surface layer; In each bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 10:1 to 30:1.

[0007] In an optional embodiment, the long-life, corrosion-resistant Al / MAX composite coating has at least one of the following characteristics: Feature 1: Long lifespan and corrosion resistant Al / MAX composite coating with a total thickness of 13μm~26μm; Feature 2: In each bottom unit, the thickness of the Al layer is 3μm~4μm; Feature 3: The thickness of the Al surface layer is 4μm~6μm; Feature 4: The MAX phase in the MAX phase layer includes the Cr2AlC phase or the Ti2AlC phase.

[0008] Secondly, the present invention provides a method for preparing a long-life corrosion-resistant Al / MAX composite coating as described in the foregoing embodiments, comprising the following steps: preparing an Al layer and an Al surface layer using magnetron sputtering composite ion source technology according to a preset structure, and preparing a MAX phase layer using arc ion plating technology.

[0009] In an optional implementation, the Al layer magnetron sputtering composite ion source deposition process includes: a sputtering current of 18A~25A for the metal Al target, a pulse negative bias voltage of 100V~150V, an ion source power of 0.5kW~1kW, an argon working pressure of 0.4Pa~0.6Pa, and a deposition time of 1.0h~2.0h.

[0010] In an optional embodiment, when the MAX phase is the Cr2AlC phase, the arc ion plating deposition process includes: Cr target current of 90A~100A, Al target current of 50A~60A, argon flow rate of 500sccm~600sccm, methane flow rate of 100sccm~200sccm, working gas pressure of 2Pa~4Pa, pulse negative bias voltage of 100V~200V, electromagnetic voltage of 10V~25V, electromagnetic frequency of 8Hz~20Hz, and deposition time of 5min~20min; When the MAX phase is the Ti2AlC phase, the arc ion plating deposition process includes: Ti target current of 90A~100A, Al target current of 50A~60A, argon flow rate of 500sccm~600sccm, methane flow rate of 100sccm~200sccm, working pressure of 2Pa~4Pa, pulse negative bias of 100V~200V, electromagnetic voltage of 10V~25V, electromagnetic frequency of 8Hz~20Hz, and deposition time of 5min~20min.

[0011] In an optional implementation, the arc ion plating process is driven by both permanent magnets and electromagnetic forces.

[0012] In an alternative implementation, the deposited Al layer is subjected to high-bias ion source bombardment before the deposition of the MAX phase layer in the same bottom cell.

[0013] In an optional implementation, the conditions for bombarding the Al layer with a high bias voltage ion source include: a pulse negative bias voltage of 500V~600V, an ion source power of 1kW~2kW, a duty cycle of 20%~30%, an argon working pressure of 0.4Pa~0.6Pa, and a bombardment time of 3min~5min.

[0014] In an optional embodiment, the deposition temperature of the entire long-life corrosion-resistant Al / MAX composite coating is 250°C to 300°C.

[0015] In an optional implementation, before depositing the first Al layer, the substrate is further subjected to degreasing treatment and surface cleaning and etching.

[0016] In an optional implementation, the cleaning and etching is performed by ion bombardment. The conditions for ion bombardment include: a pulse negative bias voltage of 800V~1000V, an ion source of 3kW~4kW, a duty cycle of 20%~30%, an argon gas pressure of 1.0Pa~1.5Pa, and a bombardment cleaning time of 5min~10min.

[0017] In an optional implementation, the Al surface layer is further subjected to shot peening post-treatment.

[0018] In an optional embodiment, the post-shot peening conditions include: 150# glass beads, pressure of 0.2MPa~0.4MPa, blasting angle of 70°~80°, and time of 10min~15min.

[0019] Thirdly, the present invention provides a mechanical component having the long-life, corrosion-resistant Al / MAX composite coating of the aforementioned embodiments.

[0020] The beneficial effects of this invention include: This invention inserts a MAX phase layer between adjacent Al layers. On one hand, the insertion of the MAX phase as a heterogeneous layer can disrupt the growth of columnar crystals in the Al layers, improving their density. On the other hand, the MAX phase itself has excellent corrosion resistance and can undergo self-healing during corrosion, which is beneficial to improving the corrosion resistance of the composite coating. This Al / MAX composite coating has strong corrosion resistance and can effectively improve the service life of parts in marine environments.

[0021] This invention, based on the use of magnetron sputtering composite ion source technology to prepare Al layers and Al surface layers, and arc ion plating technology to prepare MAX phase layers, further enhances the compactness of the Al layer by employing interfacial ion source bombardment. Simultaneously, it utilizes low-temperature deposition of the MAX phase to reduce the impact of high temperatures on the Al layer's compactness, thereby ensuring the compatibility of the deposition processes of the Al layer and the MAX phase layer and improving the bonding effect between layers. This preparation method is simple, environmentally friendly, and easily scalable for large-scale industrial production. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A photograph of the Al / MAX composite coating prepared in Example 1 of this invention after undergoing a neutral salt spray test for 1000 hours. Figure 2 A photograph of the Al / MAX composite coating prepared in Example 2 of this invention after undergoing a neutral salt spray test for 1000 hours. Figure 3 A photograph of the Al / MAX composite coating prepared in Example 3 of this invention after undergoing a neutral salt spray test for 1000 hours. Figure 4 This is a photograph of the Al / MAX composite coating prepared in Comparative Example 1 of this invention after undergoing a neutral salt spray test for 1000 hours. Figure 5 This is a photograph of the Al / MAX composite coating prepared in Comparative Example 2 of this invention after undergoing a neutral salt spray test for 1000 hours. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] The following is a detailed description of the long-life corrosion-resistant Al / MAX composite coating, its preparation method, and its application provided by the present invention.

[0026] This invention provides a long-life corrosion-resistant Al / MAX composite coating, which includes a base layer and a top layer; The bottom layer consists of at least one bottom layer unit, and each bottom layer unit consists of an Al layer and a MAX phase layer; in two adjacent bottom layer units, the Al layer and the MAX phase layer are alternately arranged. The surface layer is an Al surface layer.

[0027] This invention inserts a MAX phase layer between adjacent Al layers. On the one hand, the insertion of the MAX phase as a heterogeneous layer can break the growth of columnar crystals in the Al layer and improve its compactness. On the other hand, the MAX phase itself has good corrosion resistance and can undergo self-healing during corrosion, which is beneficial to improving the corrosion resistance of the composite coating.

[0028] In this invention, the thickness ratio of the Al layer to the MAX phase layer in each bottom unit is 10:1 to 30:1, such as 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 28:1 or 30:1, or other values ​​within the range of 10:1 to 30:1.

[0029] If the thickness ratio of the Al layer to the MAX phase layer in each bottom unit is less than 10:1 (e.g., 8:1), the MAX phase layer will be too thick, resulting in more micro-defects during the arc ion plating process, which is not conducive to preventing the invasion of corrosive media. If the thickness ratio of the Al layer to the MAX phase layer in each bottom unit is greater than 30:1 (e.g., 35:1), it is not conducive to breaking the columnar crystals of the Al layer, and the improvement in corrosion resistance life is not significant.

[0030] In some optional embodiments, the total thickness of the long-life corrosion-resistant Al / MAX composite coating can be 13μm to 26μm, such as 13μm, 15μm, 18μm, 20μm, 22μm, 25μm or 26μm, or other values ​​within the range of 13μm to 26μm.

[0031] If the total thickness of the long-life corrosion-resistant Al / MAX composite coating is less than 13μm, there are fewer alternating interfaces in the bottom layer, which is not conducive to preventing the intrusion of corrosive media; if the total thickness of the long-life corrosion-resistant Al / MAX composite coating is greater than 26μm, the bonding strength is reduced, which is not conducive to post-shot peening treatment.

[0032] In some alternative implementations, the thickness of the Al layer in each bottom unit can be 3μm to 4μm, such as 3μm, 3.5μm or 4μm, or other values ​​in the range of 3μm to 4μm.

[0033] If the thickness of the Al layer in each bottom unit is less than 3 μm, it is not conducive to surface strengthening by high bias voltage bombardment of the ion source; if the thickness of the Al layer in each bottom unit is greater than 4 μm, it is not conducive to the blocking of columnar crystals.

[0034] In some alternative implementations, the thickness of the Al layer can be 4μm to 6μm, such as 4μm, 4.5μm, 5μm, 5.5μm or 6μm, or other values ​​within the range of 4μm to 6μm.

[0035] If the thickness of the Al surface layer is less than 4 μm, it is not conducive to post-shot peening treatment; if the thickness of the Al surface layer is greater than 6 μm, the bonding strength is poor.

[0036] In some alternative embodiments, the MAX phase in the MAX phase layer may include the Cr2AlC phase or the Ti2AlC phase. It should be noted that the Ti3SiC2 phase is not used in this application because Ti3SiC2 is not easy to form a MAX phase at low temperatures and may form other impurity phases.

[0037] In some alternative implementations, the density of the long-life, corrosion-resistant Al / MAX composite coating is >99%.

[0038] As mentioned above, the Al / MAX composite coating provided by this invention has strong corrosion resistance and can effectively improve the service life of parts in marine environments.

[0039] Accordingly, the present invention also provides a method for preparing the above-mentioned long-life corrosion-resistant Al / MAX composite coating, which may include the following steps: preparing an Al layer and an Al surface layer using magnetron sputtering composite ion source technology according to a preset structure, and preparing a MAX phase layer using arc ion plating technology.

[0040] It should be noted that studies have shown that while coatings prepared with MAX phase materials possess certain corrosion resistance, they still cannot meet the requirements for long-term service in marine environments. The inventors attempted to composite MAX phase materials with Al materials in multiple layers, but found that MAX phase coatings typically require deposition at higher temperatures, which affects the density of the low-melting-point Al coating, and there is a significant compatibility issue between the two heterogeneous layers. Based on this, the inventors creatively proposed the aforementioned specific preparation method through continuous improvement. Building upon the use of magnetron sputtering composite ion source technology to prepare the Al layer and Al surface layer, and arc ion plating technology to prepare the MAX phase layer, the method further enhances the density of the Al layer by employing interfacial ion source bombardment, and by using low-temperature deposition of the MAX phase to reduce the impact of high temperatures on the density of the Al layer. This ensures the compatibility of the deposition processes of the Al layer and the MAX phase layer, and improves the bonding effect between layers.

[0041] In some optional embodiments, the Al layer magnetron sputtering composite ion source deposition process may include: a sputtering current of 18A~25A (e.g., 18A, 19A, 20A, 21A, 22A, 23A, 24A, or 25A for the metallic Al target) and a pulsed negative bias of 100V~150V (e.g., 100V, 105V, 110V, 115V, 120V, 125V, 130V, 135V, or 140V). The ion source power is 0.5kW~1kW (e.g., 0.5kW, 0.6kW, 0.7kW, 0.8kW, 0.9kW or 1kW), the argon working pressure is 0.4Pa~0.6Pa (e.g., 0.4Pa, 0.45Pa, 0.5Pa, 0.55Pa or 0.6Pa), and the deposition time is 1.0h~2.0h (e.g., 1h, 1.5h or 2h).

[0042] When ion source-assisted deposition of Al layer is used, if the ion source is below 0.5kW, the low energy results in fewer Al and Ar ions being ionized, which cannot provide additional energy to make the aluminum layer denser. If the ion source is above 1kW, the high-energy plasma bombardment of the deposited Al layer will form microscopic defects, which is detrimental to its corrosion resistance.

[0043] In some optional embodiments, when the MAX phase is the Cr2AlC phase, the arc ion plating deposition process may include: a Cr target current of 90A~100A (e.g., 90A, 95A, or 100A), an Al target current of 50A~60A (e.g., 50A, 55A, or 60A), an argon flow rate of 500sccm~600sccm (e.g., 500sccm, 520sccm, 550sccm, 580sccm, or 600sccm), and a methane flow rate of 100sccm~200sccm (e.g., 100sccm, 120sccm, 150sccm, 1...). The working pressure is 2Pa~4Pa (e.g., 2Pa, 2.5Pa, 3Pa, 3.5Pa or 4Pa), the pulse negative bias voltage is 100V~200V (e.g., 100V, 150V or 200V), the electromagnetic voltage is 10V~25V (e.g., 10V, 15V, 20V or 25V), the electromagnetic frequency is 8Hz~20Hz (e.g., 8Hz, 10Hz, 12Hz, 15Hz, 18Hz or 20Hz), and the deposition time is 5min~20min (e.g., 5min, 10min, 15min or 20min).

[0044] Using a suitable working gas pressure ensures that the MAX phase coating can be formed even at low temperatures. When the working gas pressure is below 2 Pa, there are fewer C sources in the plasma, and a large number of C-deficient phases exist in the MAX phase coating. When the working gas pressure is above 4 Pa, the plasma free path becomes shorter and the energy decreases, which is not conducive to the formation of the MAX phase at low temperatures.

[0045] When the MAX phase is the Ti2AlC phase, the arc ion plating deposition process may include: a Ti target current of 90A~100A (e.g., 90A, 95A, or 100A), an Al target current of 50A~60A (e.g., 50A, 55A, or 60A), an argon flow rate of 500sccm~600sccm (e.g., 500sccm, 520sccm, 550sccm, 580sccm, or 600sccm), and a methane flow rate of 100sccm~200sccm (e.g., 100sccm, 120sccm, 150sccm, or 180sccm). (e.g., 200 sccm, etc.), working air pressure 2 Pa~4 Pa (e.g., 2 Pa, 2.5 Pa, 3 Pa, 3.5 Pa or 4 Pa, etc.), pulse negative bias voltage 100 V~200 V (e.g., 100 V, 150 V or 200 V, etc.), electromagnetic voltage 10 V~25 V (e.g., 10 V, 15 V, 20 V or 25 V, etc.), electromagnetic frequency 8 Hz~20 Hz (e.g., 8 Hz, 10 Hz, 12 Hz, 15 Hz, 18 Hz or 20 Hz, etc.), deposition time 5 min~20 min (e.g., 5 min, 10 min, 15 min or 20 min, etc.).

[0046] Using a suitable working gas pressure ensures that the MAX phase coating can be formed even at low temperatures. When the working gas pressure is below 2 Pa, there are fewer C sources in the plasma, and a large number of C-deficient phases exist in the MAX phase coating. When the working gas pressure is above 4 Pa, the plasma free path becomes shorter and the energy decreases, which is not conducive to the formation of the MAX phase at low temperatures.

[0047] In some alternative implementations, the arc ion plating process is driven by both permanent magnets and electromagnetic forces. This method offers advantages over conventional permanent magnet-driven methods, including higher plasma energy density and denser coatings.

[0048] In some alternative implementations, before depositing the MAX phase layer in the same bottom cell, the deposited Al layer is bombarded with a high bias voltage ion source to improve the compactness of the Al layer and the bonding effect between the MAX phase layer and the Al layer.

[0049] In some optional embodiments, the conditions for bombarding the Al layer with a high bias voltage ion source include: a pulse negative bias voltage of 500V~600V (e.g., 500V, 550V, or 600V), an ion source power of 1kW~2kW (e.g., 1kW, 1.5kW, or 2kW), a duty cycle of 20%~30% (e.g., 20%, 25%, or 30%), an argon working pressure of 0.4Pa~0.6Pa (e.g., 0.4Pa, 0.45Pa, 0.5Pa, 0.55Pa, or 0.6Pa), and a bombardment time of 3min~5min (e.g., 3min, 3.5min, 4min, 4.5min, or 5min).

[0050] When ion source-assisted bombardment of the Al layer is used, the plasma energy decreases when the ion source power is below 1kW, and the bombardment effect on the Al layer is not obvious; when the ion source power is above 2kW, the Al layer is bombarded and thinned, which is not conducive to long-life corrosion resistance.

[0051] In some alternative embodiments, the deposition temperature of the entire long-life corrosion-resistant Al / MAX composite coating is 250°C to 300°C, such as 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, etc., or other values ​​within the range of 250°C to 300°C.

[0052] If the deposition temperature of the entire long-life corrosion-resistant Al / MAX composite coating is below 250℃, it is not conducive to the formation of the MAX phase; if the deposition temperature of the entire long-life corrosion-resistant Al / MAX composite coating is above 300℃, it will lead to a significant reduction in the density of the low-melting-point Al coating.

[0053] In some alternative implementations, the substrate is further subjected to degreasing and surface cleaning and etching before the deposition of the first Al layer.

[0054] In some optional embodiments, the cleaning and etching can be performed by ion bombardment. The conditions for ion bombardment may include: a pulse negative bias voltage of 800V~1000V (e.g., 800V, 850V, 900V, 950V or 1000V), an ion source of 3kW~4kW (e.g., 3kW, 3.5kW or 4kW), a duty cycle of 20%~30% (e.g., 20%, 25% or 30%), an argon gas pressure of 1.0Pa~1.5Pa (e.g., 1.0Pa, 1.1Pa, 1.2Pa, 1.3Pa, 1.4Pa or 1.5Pa), and a bombardment cleaning time of 5min~10min (e.g., 5min, 6min, 7min, 8min, 9min or 10min).

[0055] In some alternative implementations, post-treatment of the Al surface layer by shot peening is also included.

[0056] In some optional embodiments, the post-shot peening conditions may include: shot beads of 150# glass, pressure of 0.2MPa~0.4MPa (e.g., 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa or 0.4MPa), blasting angle of 70°~80° (e.g., 70°, 75° or 80°), and time of 10min~15min (e.g., 10min, 11min, 12min, 13min, 14min or 15min).

[0057] Shot peening physically strengthens the density of the Al surface layer and improves the bonding strength of the composite coating.

[0058] In addition, the present invention also provides a mechanical component having the above-mentioned long-life corrosion-resistant Al / MAX composite coating.

[0059] Mechanical components may, for example, include fasteners or structural parts.

[0060] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0061] Example 1 This embodiment provides a long-life, corrosion-resistant Al / MAX composite coating, the preparation method of which is as follows: S1: Degreasing treatment of the substrate: The high-strength steel substrate is ultrasonically cleaned in an alkaline metal cleaning solution for 20 minutes, then ultrasonically cleaned in acetone and alcohol for 5 minutes respectively, dried and placed in a vacuum chamber for later use.

[0062] S2: Perform surface cleaning and etching on the degreased substrate: Set the base vacuum level in the vacuum chamber to 5.0 × 10⁻⁶. -3 Pa, temperature set to 250℃. Before deposition, argon gas was introduced into the vacuum chamber at a pressure of 1.5 Pa, the ion source was 3 kW, the duty cycle was 30%, and the substrate was cleaned with a negative bias voltage of 800 V for 10 min.

[0063] S3: Deposition of the first bottom layer unit: S31: An Al layer was deposited using an Al layer magnetron sputtering composite ion source. The conditions included: argon gas was introduced into the cavity, the working pressure was 0.4 Pa, the pulse negative bias voltage was 100 V, the ion source power was 0.8 kW, the magnetron sputtering current of the Al target was 18 A, the temperature was 250 °C, the deposition time was 60 min, and the thickness of the Al layer was 3 μm.

[0064] S32: The Al layer in the bottom unit is bombarded with a high bias voltage ion source under the following conditions: pulse negative bias voltage of 500V, ion source power of 1kW, duty cycle of 30%, argon working pressure of 0.4Pa, and bombardment time of 5min.

[0065] S33: An arc ion plating (driven by both permanent magnet and electromagnetic) deposition process was used to deposit a Cr2AlC phase layer. The conditions included: argon and methane were introduced into the cavity as reactant gases, with an argon flow rate of 500 sccm and a methane flow rate of 100 sccm. The current of the Cr target was 90 A and the current of the Al target was 50 A. The temperature was 250 °C, the gas pressure was 2 Pa, the negative bias voltage was 100 V, the electromagnetic voltage was 10 V, the electromagnetic frequency was 8 Hz, the deposition time was 5 min, and the thickness of the Cr2AlC phase layer was 0.1 μm.

[0066] S4: Repeat S3 twice more to deposit the other two bottom layers.

[0067] S5: Deposition of Al surface layer using magnetron sputtering composite ion source for Al layer, with the following conditions: argon gas is introduced into the cavity, working pressure is 0.6 Pa, pulse negative bias voltage is 150 V, magnetron sputtering current of Al target is 25 A, temperature is 250 ℃, deposition time is 60 min, and Al surface layer thickness is 4 μm.

[0068] S6: Shot peening of the Al surface layer, with the following conditions: using 150# glass beads, pressure of 0.2MPa, and blasting angle of 70°. o The time is 10 minutes.

[0069] The total thickness of the long-life corrosion-resistant Al / MAX composite coating provided in this embodiment is (3+0.1)×3+4=13.3μm; in a single bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 30:1.

[0070] Example 2 The difference between this embodiment and Embodiment 1 is that: S2: Perform surface cleaning and etching on the degreased substrate: Set the base vacuum level in the vacuum chamber to 5.0 × 10⁻⁶. -3 Pa, temperature set to 300℃. Before deposition, argon gas was introduced into the vacuum chamber at a pressure of 1.0 Pa, the ion source was 4 kW, the duty cycle was 20%, and a negative bias voltage of 1000 V was applied to the substrate for cleaning for 5 min.

[0071] S31: An Al layer was deposited using an Al layer magnetron sputtering composite ion source. The conditions included: argon gas was introduced into the cavity, the working pressure was 0.6 Pa, the pulse negative bias voltage was 150 V, the ion source power was 1.0 kW, the magnetron sputtering current of the Al target was 25 A, the temperature was 300 ℃, the deposition time was 60 min, and the thickness of the Al layer was 4 μm.

[0072] S32: The Al layer in the bottom unit is bombarded with a high bias voltage ion source under the following conditions: pulse negative bias voltage of 600V, ion source power of 2kW, duty cycle of 20%, argon working pressure of 0.6Pa, and bombardment time of 3min.

[0073] S33: The Ti2AlC phase layer was deposited using an arc ion plating (driven by both permanent magnet and electromagnetic) deposition process. The conditions included: argon and methane were introduced into the cavity as reactant gases, with an argon flow rate of 600 sccm and a methane flow rate of 200 sccm. The Ti target current was 100 A, the Al target current was 60 A, the temperature was 300 °C, the gas pressure was 4 Pa, the negative bias voltage was 200 V, the electromagnetic voltage was 25 V, the electromagnetic frequency was 20 Hz, the deposition time was 20 min, and the thickness of the Ti2AlC phase layer was 0.4 μm.

[0074] S4: Repeat S3 three more times to deposit the other three bottom layers.

[0075] S5: Deposition of Al surface layer using magnetron sputtering composite ion source for Al layer, with the following conditions: argon gas is introduced into the cavity, working pressure is 0.5 Pa, pulse negative bias voltage is 100 V, magnetron sputtering current of Al target is 20 A, temperature is 300 ℃, deposition time is 60 min, and Al surface layer thickness is 5 μm.

[0076] S6: Shot peening of the Al surface layer, with the following conditions: using 150# glass beads, pressure of 0.3MPa, and blasting angle of 70°. o The time is 15 minutes.

[0077] The total thickness of the long-life corrosion-resistant Al / MAX composite coating provided in this embodiment is (4+0.4)×4+5=22.6μm; in a single bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 10:1.

[0078] Example 3 The difference between this embodiment and Embodiment 1 is that: S2: Perform surface cleaning and etching on the degreased substrate: Set the base vacuum level in the vacuum chamber to 5.0 × 10⁻⁶. -3Pa, temperature set to 280℃. Before deposition, argon gas was introduced into the vacuum chamber at a pressure of 1.2 Pa, the ion source was 3.5 kW, the duty cycle was 25%, and a negative bias voltage of 700 V was applied to the substrate for cleaning for 4 min.

[0079] S31: An Al layer was deposited using an Al layer magnetron sputtering composite ion source. The conditions included: argon gas was introduced into the cavity, the working pressure was 0.5 Pa, the pulse negative bias voltage was 130 V, the ion source power was 0.5 kW, the magnetron sputtering current of the Al target was 20 A, the temperature was 280 °C, the deposition time was 50 min, and the thickness of the Al layer was 4 μm.

[0080] S32: The Al layer in the bottom unit is bombarded with a high bias voltage ion source under the following conditions: pulse negative bias voltage of 550V, ion source power of 1.5kW, duty cycle of 25%, argon working pressure of 0.5Pa, and bombardment time of 4min.

[0081] S33: Cr2AlC phase layer was deposited using an arc ion plating (driven by both permanent magnet and electromagnetic) deposition process. The conditions included: argon and methane were introduced into the cavity as reactant gases, with an argon flow rate of 550 sccm and a methane flow rate of 150 sccm. The current of the Cr target was 100 A, the current of the Al target was 50 A, the temperature was 280 °C, the gas pressure was 3 Pa, the negative bias voltage was 150 V, the electromagnetic voltage was 18 V, the electromagnetic frequency was 10 Hz, the deposition time was 10 min, and the thickness of the Cr2AlC phase layer was 0.2 μm.

[0082] S4: Repeat S3 four more times to deposit the other four bottom layers.

[0083] S5: Deposition of Al surface layer using magnetron sputtering composite ion source for Al layer, with the following conditions: argon gas is introduced into the cavity, working pressure is 0.5 Pa, pulse negative bias voltage is 100 V, magnetron sputtering current of Al target is 20 A, temperature is 280 ℃, deposition time is 60 min, and Al surface layer thickness is 5 μm.

[0084] S6: Shot peening of the Al surface layer, with the following conditions: using 150# glass beads, pressure of 0.4MPa, and blasting angle of 80°. o The time is 12 minutes.

[0085] The total thickness of the long-life corrosion-resistant Al / MAX composite coating provided in this embodiment is (4+0.2)×5+5=26μm; in a single bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 20:1.

[0086] Comparative Example 1 The difference between this comparative example and Example 1 is that in S4, S3 is repeated once more to deposit another bottom layer unit.

[0087] The total thickness of the long-life corrosion-resistant Al / MAX composite coating provided in this comparative example is (3+0.1)×2+4=10.2μm; in a single bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 30:1.

[0088] Comparative Example 2 The difference between this comparative example and Example 1 is that the deposition temperature for S3 to S5 is 350°C.

[0089] Comparative Example 3 The difference between this comparative example and Example 1 is that the conditions in S32 include: a pulse negative bias voltage of 600V, an ion source power of 3kW, a duty cycle of 100%, an argon working pressure of 1.05Pa, and a bombardment time of 3min.

[0090] Comparative Example 4 The difference between this comparative example and Example 1 is that step S6 is omitted.

[0091] Comparative Example 5 The difference between this comparative example and Example 1 is that step S32 is omitted in S31 and S33, and in S33, argon and methane are introduced into the cavity as reaction gases, with an argon flow rate of 300 sccm, a methane flow rate of 200 sccm, a Cr target current of 60 A, an Al target current of 100 A, a temperature of 200 °C, a gas pressure of 2 Pa, a negative bias of 100 V, an electromagnetic voltage of 10 V, an electromagnetic frequency of 8 Hz, a deposition time of 5 min, and a Cr2AlC phase layer thickness of 0.5 μm.

[0092] Comparative Example 6 The difference between this comparative example and Example 1 is that it does not contain the MAX phase layer, but only an Al layer with a thickness of 16.4 μm.

[0093] Comparative Example 7 The difference between this comparative example and Example 1 is that it does not contain an Al layer, but only a MAX phase layer with a thickness of 16.4 μm.

[0094] Comparative Example 8 The difference between this comparative example and Example 1 is that the thickness ratio of the Al layer to the MAX phase layer in each bottom unit is 5:1.

[0095] Comparative Example 9 The difference between this comparative example and Example 1 is that the thickness ratio of the Al layer to the MAX phase layer in each bottom unit is 35:1.

[0096] Comparative Example 10 The difference between this comparative example and Example 1 is that the total thickness of the long-life corrosion-resistant Al / MAX composite coating is 30 μm.

[0097] Comparative Example 11 The difference between this comparative example and Example 1 is that the thickness of the Al layer in each bottom unit is 2 μm.

[0098] Comparative Example 12 The difference between this comparative example and Example 1 is that the thickness of the Al layer in each bottom unit is 5 μm.

[0099] Comparative Example 13 The difference between this comparative example and Example 1 is that the thickness of the Al surface layer is 3μm~6μm.

[0100] Comparative Example 14 The difference between this comparative example and Example 1 is that the MAX phase in the MAX phase layer is the Ti3SiC2 phase.

[0101] Comparative Example 15 The difference between this comparative example and Example 1 is that the arc ion plating treatment uses a common permanent magnet drive method.

[0102] Comparative Example 16 The difference between this comparative example and Example 1 is that step S32 is absent in S31 and S33.

[0103] Comparative Example 17 The difference between this comparative example and Example 1 is that in S31, the ion source power of the Al layer magnetron sputtering composite ion source deposition process is 0.2kW.

[0104] Comparative Example 18 The difference between this comparative example and Example 1 is that in S31, the ion source power of the Al layer magnetron sputtering composite ion source deposition process is 1.2kW.

[0105] Comparative Example 19 The difference between this comparative example and Example 1 is that in S33, the gas pressure for depositing the Cr2AlC phase layer using the arc ion plating (driven by both permanent magnet and electromagnetic) deposition process is 1 Pa.

[0106] Comparative Example 20 The difference between this comparative example and Example 1 is that in S33, the gas pressure for depositing the Cr2AlC phase layer using the arc ion plating (driven by both permanent magnet and electromagnetic) deposition process is 5 Pa.

[0107] Test case The Al / MAX composite coatings prepared in Examples 1-3 and Comparative Examples 1-20 were subjected to neutral salt spray tests. The test conditions and methods were as follows: continuous spray test was used, with a temperature of 35℃±2℃, a 5%±1% NaCl solution (mass fraction), and a pH of 6.5-7.2 for the salt spray solution. The tilt angle of the sample surface in the salt spray chamber was 45°±5°. The effect of the salt spray test was characterized by observing the time it took for corrosion products to form.

[0108] After undergoing a neutral salt spray test for 1000 hours, the appearance of the Al / MAX composite coating in Example 1 is as follows: Figure 1 As shown, by Figure 1 As can be seen, the Al / MAX composite coating did not exhibit red rust on the substrate, indicating that the coating still provides protection and has excellent corrosion resistance.

[0109] After undergoing a neutral salt spray test for 1000 hours, the appearance of the Al / MAX composite coating in Example 2 is as follows: Figure 2 As shown, by Figure 2 As can be seen, the Al / MAX composite coating did not exhibit red rust on the substrate, indicating that the coating still provides protection and has excellent corrosion resistance.

[0110] After undergoing a neutral salt spray test for 1000 hours, the appearance of the Al / MAX composite coating in Example 3 is as follows: Figure 3 As shown, by Figure 3 As can be seen, the Al / MAX composite coating did not exhibit red rust on the substrate, indicating that the coating still provides protection and has excellent corrosion resistance.

[0111] After a 1000-hour neutral salt spray test, the Al / MAX composite coating of Example 1 showed the following appearance: Figure 4 As shown, by Figure 4 It can be seen that the Al / MAX composite coating has a lot of red rust, indicating that the substrate has been corroded and the coating has lost its protective function.

[0112] After a 1000-hour neutral salt spray test, the Al / MAX composite coating of Comparative Example 2 showed the following appearance: Figure 5 As shown, by Figure 5 It can be seen that the Al / MAX composite coating has a lot of red rust, indicating that the substrate has been corroded and the coating has lost its protective function.

[0113] After a 1000-hour neutral salt spray test, the Al / MAX composite coating in Comparative Example 3 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0114] After a 1000-hour neutral salt spray test, the Al / MAX composite coating in Example 4 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0115] After a 1000-hour neutral salt spray test, the Al / MAX composite coating in Example 5 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0116] After a neutral salt spray test of 480 h, the Al / MAX composite coating of Example 6 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0117] After a neutral salt spray test of 312 hours, the Al / MAX composite coating of Example 7 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0118] After a neutral salt spray test of 576 hours, the Al / MAX composite coating of Example 8 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0119] After a neutral salt spray test of 720 h, the Al / MAX composite coating of Example 9 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0120] After a 1000-hour neutral salt spray test, the Al / MAX composite coating of Comparative Example 10 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0121] After a neutral salt spray test of 840 hours, the Al / MAX composite coating of Comparative Example 11 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0122] After a 960-hour neutral salt spray test, the Al / MAX composite coating in Comparative Example 12 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0123] After a 960-hour neutral salt spray test, the Al / MAX composite coating in Comparative Example 13 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0124] After a neutral salt spray test of 576 hours, the Al / MAX composite coating in Comparative Example 14 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0125] After 840 hours of neutral salt spray testing, the Al / MAX composite coating of Comparative Example 15 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0126] After a neutral salt spray test of 720 h, the Al / MAX composite coating of Comparative Example 16 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0127] After a neutral salt spray test of 720 h, the Al / MAX composite coating of Comparative Example 17 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0128] After a neutral salt spray test of 768 hours, the Al / MAX composite coating of Comparative Example 18 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0129] After a neutral salt spray test of 576 hours, the Al / MAX composite coating of Example 19 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0130] After a 624-hour neutral salt spray test, the Al / MAX composite coating in Comparative Example 20 showed a large amount of red rust, indicating that the substrate had been corroded and the coating had lost its protective function.

[0131] In summary, the Al / MAX composite coating preparation method provided by this invention is simple, environmentally friendly, and easy to achieve large-scale industrial production. The Al / MAX composite coating has high corrosion resistance and can effectively improve the service life of parts in marine environments. It can be used in high-end manufacturing and aerospace fields.

[0132] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A long-life, corrosion-resistant Al / MAX composite coating, characterized in that, The long-life, corrosion-resistant Al / MAX composite coating comprises a base layer and a top layer; The bottom layer is composed of at least one bottom layer unit, and each bottom layer unit is composed of an Al layer and a MAX phase layer; in two adjacent bottom layer units, the Al layer and the MAX phase layer are alternately arranged. The surface layer is an Al surface layer; In each bottom unit, the thickness ratio of the Al layer to the MAX phase layer is 10:1 to 30:

1.

2. The long-life, corrosion-resistant Al / MAX composite coating according to claim 1, characterized in that, The long-life, corrosion-resistant Al / MAX composite coating has at least one of the following characteristics: Feature 1: The total thickness of the long-life, corrosion-resistant Al / MAX composite coating is 13μm~26μm; Feature 2: In each of the bottom units, the thickness of the Al layer is 3μm~4μm; Feature 3: The thickness of the Al surface layer is 4μm~6μm; feature 4: The MAX phase in the MAX phase layer includes the Cr2AlC phase or the Ti2AlC phase.

3. A method for preparing a long-life, corrosion-resistant Al / MAX composite coating as described in claim 1 or 2, characterized in that, The process includes the following steps: preparing an Al layer and an Al surface layer using magnetron sputtering composite ion source technology according to a preset structure, and preparing a MAX phase layer using arc ion plating technology.

4. The preparation method according to claim 3, characterized in that, The Al layer magnetron sputtering composite ion source deposition process includes: sputtering current of 18A~25A for the metal Al target, pulse negative bias voltage of 100V~150V, ion source power of 0.5kW~1kW, argon working pressure of 0.4Pa~0.6Pa, and deposition time of 1.0h~2.0h.

5. The preparation method according to claim 3, characterized in that, When the MAX phase is the Cr2AlC phase, the arc ion plating deposition process includes: Cr target current of 90A~100A, Al target current of 50A~60A, argon flow rate of 500sccm~600sccm, methane flow rate of 100sccm~200sccm, working pressure of 2Pa~4Pa, pulse negative bias of 100V~200V, electromagnetic voltage of 10V~25V, electromagnetic frequency of 8Hz~20Hz, and deposition time of 5min~20min. Preferably, the arc ion plating process is driven by both permanent magnets and electromagnetic forces.

6. The preparation method according to claim 3, characterized in that, When the MAX phase is Ti2AlC phase, the arc ion plating deposition process includes: Ti target current of 90A~100A, Al target current of 50A~60A, argon flow rate of 500sccm~600sccm, methane flow rate of 100sccm~200sccm, working pressure of 2Pa~4Pa, pulse negative bias of 100V~200V, electromagnetic voltage of 10V~25V, electromagnetic frequency of 8Hz~20Hz, and deposition time of 5min~20min. Preferably, the arc ion plating process is driven by both permanent magnets and electromagnetic forces.

7. The preparation method according to claim 3, characterized in that, In the same bottom cell, before depositing the MAX phase layer, the already deposited Al layer is bombarded with a high bias voltage ion source. Preferably, the conditions for bombarding the Al layer with a high bias voltage ion source include: pulse negative bias voltage of 500V~600V, ion source power of 1kW~2kW, duty cycle of 20%~30%, argon working pressure of 0.4Pa~0.6Pa, and bombardment time of 3min~5min.

8. The preparation method according to claim 3, characterized in that, The deposition temperature of the entire long-life corrosion-resistant Al / MAX composite coating is 250℃~300℃.

9. The preparation method according to any one of claims 3 to 8, characterized in that, Before depositing the first Al layer, the process also includes degreasing the substrate and surface cleaning and etching. Preferably, the cleaning and etching are performed by ion bombardment. The conditions for ion bombardment include: pulse negative bias voltage of 800V~1000V, ion source of 3kW~4kW, duty cycle of 20%~30%, argon gas pressure of 1.0Pa~1.5Pa, and bombardment cleaning time of 5min~10min.

10. The preparation method according to any one of claims 3 to 8, characterized in that, It also includes post-treatment of the Al surface layer by shot peening; Preferably, the post-shot peening conditions include: 150# glass beads, pressure of 0.2MPa~0.4MPa, blasting angle of 70°~80°, and time of 10min~15min.

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